This invention relates in general to covers for open topped compartments and, more specifically, to a cover that is easily moved between stowed and deployed, covering, positions and maintains control over loose material in an open topped compartment.
Open topped compartments such as dump trucks, vehicle trailers, storage bins and the like used to store or carry particulate material are subject to having the material fall or blow out in use. With trucks or trailers hauling sand, gravel, dirt or similar materials, having portions of the load fall out onto the roadway is undesirable both from the point of view of littering the area and the danger of the material striking a following vehicle, possibly breaking the windshield and causing an accident. Similarly, trucks or trailers carrying lightweight materials such as plant clippings being taken to a landfill, mulch materials, harvested plants such as cotton, or fixed storage bins holding such materials are liable to having gusty winds blow portions of the contents out of the vehicle or bin.
Many localities now have laws requiring that all such open topped vehicle compartments be covered when containing loose or lightweight materials. Often, the loads are simply covered with a tarpaulin that is tied to the edges of the open top at intervals around the opening. While sometimes effective, such tarpaulins are difficult for one person to put in place, especially in windy conditions and material may fall out between tie-down points where the material is heaped above the top of the compartment. Installing the cover is time consuming and must be carefully done to prevent an edge of the cover from coming loose and allowing loss of part of the loose contents.
Attempts have been made to provide more convenient covers which can be moved from a stowed position to a covering position by one person. Generally, these systems have the cover wrapped around a roller at one end of the open top while the vehicle or bin is being loaded or emptied. Once filled, the cover is pulled to unroll it over the opening and fastened to the end opposite the roller. When the load is to be removed, the fasteners are unfastened and the roller is rotated, such as by a crank, to roll up the cover. While more convenient than a loose tarpaulin, these cover systems are difficult to deploy where the load is heaped up at the center above the height of the roller. In such cases the cover often only contacts the peak of the heaped material and does not conform to the shape of the heaped load, so that air can enter and portions of the load can blow or be jostled out of the opening.
Thus, there is a continuing need for improvements in covers for open topped compartments that are easily installed by one person, even where the load is in a heap extending up above the edges of the opening, and which will engage and fully restrain movement of the loaded material.